Have you heard the good news? Microsoft has just released a SL 4 update addressing some reported issues. Check Tim Heuer’s blog for details.
This update is really important in regards to the Popups/ChildWindow automation. Until now the Telerik Automated Testing Tools required to track your popups manually which was inconvenient for some customers. With the latest official release of the product though and the new SL4 update this is no longer needed. Just upgrade the SL4 runtime on your machine and start automating those popups!